For creating extracts you will want to use the Tableau Rest API: https://onlinehelp.tableau.com/current/pro/desktop/en-us/help.htm#extracting_TDE_API.html%3FTocPath%3DConnect%2520to%252…
As for the .hyper file not taking decimal places. Can you please ellaborate on this a little more. Does it throw an error when trying to create it?
Hope this helps!